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Volume 20, Issue 2, Summer 2002

The Gray Bat's Survival

By Robert Locke

The gray bat - feared, hated, and casually killed -- was tumbling toward extinction in 1959. These cave-dwelling bats, which once filled the evening skies over much of eastern North America, were so vulnerable to human destruction that hundreds of thousands were being slaughtered in single acts.

Then a Tennessee teenager took an interest. Now, after more than four decades of clearing barriers and winning allies, the revitalized gray bat has achieved a rare and wonderful triumph: Myotis grisescens seems ready to graduate from the endangered species list. That success spawned many others, for Merlin Tuttle's long struggle to save the beleaguered gray bat gave birth in 1982 to Bat Conservation International. And it defined the commitment and the philosophy that have guided the organization for 20 years.

The story of the gray bat is in many ways the story of BCI

It began when Merlin, then a high school student, discovered a colony of gray bats (now also called gray myotis) in Baloney Cave, a few miles from his home in Knoxville, Tennessee. In 1959, gray bats were generally considered non-migratory mammals that lived in the same caves year-round. What Merlin saw at Baloney Cave suggested a different picture. Thousands of gray bats swept into the cave in the spring and again in the fall, each time mysteriously disappearing after only a few days. To the teenager, that looked a lot like migratory behavior.

Convincing his parents to take him to the Smithsonian Institution in Washington, D.C., Merlin discussed his observations with leading bat specialists. They were impressed enough to issue him bat bands through the U.S. Fish and Wildlife Service. They challenged him to find out where the bats were going and by October 1960, he had captured, tagged, and released several hundred.

In a remarkable piece of luck, he and his father found many of those banded bats less than two months later, in another cave more than 100 miles (160 kilometers) north of Knoxville. Merlin had demonstrated not only that his bats migrated, but that they had traveled north, rather than south, to winter hibernation sites.

Building on this quick success, Merlin settled in for the long haul. He eventually banded 40,182 gray bats -- and recaptured over 20,000 -- at hundreds of locations in Tennessee, Alabama, Georgia, Florida, North Carolina, Virginia, Kentucky, and Missouri. Twenty years of work firmly documented some of North America's longest bat migrations and produced his Ph.D. dissertation in population ecology at the University of Kansas.

In addition to a treasure of new scientific data, Merlin also found evidence of a disaster in the making, a discovery that was to chart the course of his life: Gray bat colonies were being devastated by humans at a frightful rate. The culprit, he soon learned, was misinformation --ignorance was driving the gray bat into extinction.

As his research took him throughout the South in search of gray bats, Merlin increasingly crawled into caves whose great ceiling domes bore the broad splashes of coffee-colored stains and pockmarks that signal long use by bats. But where once gray bats had carpeted hundreds of square feet of limestone ceiling, he often found bats clustered over a space no bigger than a serving platter -- or no bats at all.

"You're too late," old-timers often said when asked for the locations of bat caves. "When I was a child, clouds of bats filled the sky. You should have been here back then. They're all gone now."

The truth was grim. Cave owners and visitors intentionally killed incredible numbers of gray bats, sometimes even pouring kerosene into their caves and igniting conflagrations that burned or suffocated all the bats inside. In 1973, Merlin brought friends to witness the spectacular evening emergence of the largest gray bat colony he'd studied. They gathered at the mouth of Hambrick Cave in northern Alabama and waited. And waited. There was no emergence. A quarter of a million bats had been killed. The entrance to the cave was scorched by fires and fireworks debris littered the floor inside. In many cases, those who killed bats were convinced they were protecting their families and neighbors from mortal danger. Local health departments, warning that bats were dangerous, were claiming that most gray bats were rabid -- though no one knew of a single instance, not even a suspected instance, in which a human, a pet, or a head of livestock had ever contracted the disease from a gray bat.

"It was," Merlin says, "hard not to be outraged when so many people were needlessly slaughtering bats that were in fact harmless and highly beneficial." The gray bat seemed to have little future.

The species is especially vulnerable since females bear just one pup per year and form large, conspicuous colonies that live in caves year-round. Single acts can kill tens or even hundreds of thousands, and the species simply cannot reproduce fast enough to overcome such losses.

The gray bats' peril was like that of the passenger pigeon a century before. Both species required large populations to survive. (Only large colonies of gray bats, which need the body heat of many individuals to raise the temperature of cool cave roosts, can successfully rear young.) The numbers are tragically deceptive -- so large it seemed both species could survive anything. Countless millions of passenger pigeons darkened the sky in flocks said to stretch for miles in 1860. Then commercial hunters turned on the pigeons, which reproduced almost as slowly as bats. In just decades, the vast flocks were reduced to a single, caged bird. That last passenger pigeon died in 1914.

In addition to the impact of intentional killing, even more gray bats were being lost because early cave explorers, with no intention of causing damage, did not realize the harm that ill-timed visits could cause at hibernation and nursery caves. Only a tiny fraction of caves meet the precise temperature needs of gray bats, especially for hibernation. Unless the few appropriate caves could be protected, the species had no chance.

By 1969, Roger Barbour and Wayne Davis, in their book Bats of America, had predicted that the gray bat probably faced extinction.

In 1976, Merlin revisited 22 of his most isolated and important study caves in Tennessee and Alabama, homes to the colonies he had considered least likely to suffer declines. Even those colonies had shrunk by more than 50 percent in just five years. They had already fallen from 1.2 million bats to 635,700 in 1970; by 1976, they had collapsed to just 293,600. The largest nursery colony of all had disappeared entirely.

The U.S. Fish and Wildlife Service, at Merlin's request, officially listed the gray bat as an endangered species in 1976. As Merlin became an active conservationist, he learned how daunting was his challenge. Not only were few people aware of the beneficial aspects of bats and their importance to the varied ecosystems they occupied, but most harbored deep-seated -- and completely misplaced -- fears of these flying mammals.

Among established conservation groups, he found little interest in championing such unpopular creatures. Endangered or not, bats couldn't compete with baby seals and panda bears. "Even conservationists looked at me like: ÔSure, next you'll try to sell us on the virtues of rattlesnakes and cockroaches.'" Protecting bats clearly would require an organization dedicated specifically to them.

Another insight came clear, a notion that was to serve as the philosophical foundation of BCI. When Merlin asked a Tennessee farmer for permission to study gray bats in a cave on his property, the farmer replied: "Sure, and while you're in there, kill as many of them as you can." Knowing the futility of arguing the point, Merlin thanked the farmer and climbed into the cave. He found the cave floor littered with the discarded wings of potato beetles, a pest much feared by local farmers. When Merlin returned with a handful of the colorful wings, the farmer understood immediately that the bats were eating his most feared pests. The next time Merlin visited, the farmer was actively protecting his bats.

"When you're trying to protect an organism that is as unpopular as bats were then, you really don't have any power," Merlin says. "You can't beat people over the head with the Endangered Species Act. You have to work diplomatically, to show them the value of protecting bats." Education is the key, education that documents the importance of bats and dispels myths about them. Ultimately, he became convinced that saving bats is a matter of showing people that bat conservation is very much in their self-interest.

Soon after the gray bat was listed as endangered, the battered species faced a potentially devastating threat. Sauta Cave in northern Alabama was the gray bats' most important remaining summer roost, a refuge for about 100,000 bats (although it had once housed more than half a million). The cave's new owner, planning to build a resort at the site, had begun dynamiting inside the cave. The state had approved an environmental impact statement that foresaw no harmful consequences of commercializing the cave, even though it sheltered the largest surviving summer colony of endangered gray bats, Alabama's only known hibernating population of endangered Indiana bats (Myotis sodalis), and the largest population of threatened Tennessee cave salamanders. Bats and salamanders were proving to be a tough sell. But persistence paid off: The U.S. Fish and Wildlife Service, with help from Merlin, acquired Sauta Cave. Now known as Blowing Wind Cave Wildlife Refuge, its growing bat population has more than doubled.

Such close calls convinced Merlin of the critical need for training programs, since even wildlife biologists of the time typically knew little about bats. He convinced the Fish and Wildlife Service to let him train several agency biologists in the skills needed to help bats. Two of them became pivotal leaders in bat conservation.

Within months of that week long training session some 25 years ago, Fred Bagley, through tremendous personal efforts, had won the federal acquisition and protection of Alabama's Fern Cave, the largest remaining hibernation cave known worldwide and winter home of more than half of the entire remaining gray bat population.

Another of those first trainees, Bob Currie, remains to this day a key leader in bat conservation. Bob has led numerous projects to protect essential bat caves throughout North America and inspired countless cavers to volunteer their time installing gates to protect caves. That early training project led directly to major payoffs: BCI's highly successful Bat Conservation and Management Workshops and its scholarship awards for young biologists. (In addition, one of BCI's most impressive and long-running accomplishments is its continuing program for cave and mine protection.)

The struggle to reverse the gray bat's slide into oblivion proved repeatedly the enormous potential of choosing cooperation and education over confrontation.

In 1977, environmentalists were frantically trying to block construction of a Tennessee Valley Authority nuclear power plant near Nashville. They sought Merlin's help in using the endangered status of gray bats to stop the project. Merlin admits to a strongly negative attitude at that time because of TVA's previously dismal track record on environmental issues, but he decided to investigate before joining the fray.

What he learned convinced him that the apparent conflict between bats and the TVA could be eliminated, at no cost, by simply rerouting a proposed power line corridor. TVA officials were delighted. The federal agency's newly hired environmental spokesperson, Ralph Jordan, conceded that the TVA might have earned the distrust of conservationists in the past, but said his job was to "change the future."

The agency owned much of the gray bats' remaining habitat, Jordan told Merlin, and "if you'll provide advice that keeps us out of trouble, we'll pass on the savings to help bats." The TVA was transformed suddenly from a potential enemy into a staunch ally -- a leader in bat conservation. Today, the Tennessee Valley Authority is one of the nation's leading protectors of gray bat caves.

Merlin founded Bat Conservation International on March 12, 1982. It grew from his firm belief in the power of carefully focused research and education, of broad collaboration, and of converting presumed enemies into allies. Re-establishing the gray bat became one of BCI's first priorities.

Merlin had been Curator of Mammals at the Milwaukee Public Museum since 1975, and BCI began its life as a nights-and-weekends operation that was headquartered in his museum office. Years would pass before BCI's reach spanned much of the world, but the seeds of the organization were sown and nurtured.

A January 2002 evaluation trip back into gray bat country demonstrates just how far this species -- and BCI -- has come. Despite early predictions, the endangered gray bat is proving quite capable of re-establishing itself if freed from human disturbance.

The preliminary report from that trip documents a dramatic recovery. One Tennessee site vividly illustrates the power of education. At Bellamy Cave, where a once-impressive colony had been beaten down to 65 bedraggled survivors, the bats have experienced an incredible rebirth. It is now the hibernation home for an amazing 91,000 gray bats. Twenty-eight years earlier, Merlin had explained how important this cave had once been for gray bats, and the owners responded by installing a fence, gate, and sign to protect the cave.

Two other Tennessee caves demonstrate the changing attitudes of other conservation groups, as well as the enormous impact of partnerships and coalition building.

Hubbards Cave, a hibernation site for meager remnants of a colony that once numbered perhaps a million gray bats, was purchased by The Nature Conservancy in 1984 and, thanks to a broad-based partnership organized jointly by BCI and the Conservancy, is now protected by the world's largest cave gates (See "An Epic Gate" on Page 10). The Hubbard colony has doubled in size and shows every sign of eventually regaining great numbers.

Pearson Cave, gated in 1989 in a combined effort by BCI, The Nature Conservancy, and The American Cave Conservation Association, has, in just over a decade, tripled its gray bat population to some 366,000.

Population counts throughout the gray bat's range confirm the remarkable conclusion that a species whose extinction was predicted as recently as 1969 is now recovering rapidly. The gray bat, while not completely safe, nonetheless seems strong enough to be removed from the list of endangered species, marking an incredible achievement by BCI and its many dedicated partners and volunteers.

Yet BCI can spare little time for celebration. The long story of the gray bat's recovery is an encouraging model, proof of what can be accomplished when committed people, united by a shared and proven philosophy, focus their energy and resources on critical conservation targets. The targets are many.